Dengue fever is a viral infection transmitted by mosquitos found in tropical and sub-tropical regions around the world. It is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death. In recent years, transmission has increased predominantly in urban and semi-urban areas and has become a major international public health concern.

Dengue is the most rapidly spreading mosquito-borne viral disease in the world. In the last 50 years, incidence has increased 30-fold with increasing geographic expansion to new countries and, in the present decade, from urban to rural settings. An estimated 50 million dengue infections occur annually and approximately 2.5 billion people live in dengue endemic countries.

Since 1998, epidemics of dengue fever and dengue haemorrhagic fever have been reported in the Region with increasing frequency and expanding geographic distribution of both the viruses and mosquito vectors. Outbreaks have been reported from Djibouti, Pakistan, Saudi Arabia, Somalia, Sudan and Yemen. In 2009 and the first half of 2010, outbreaks of dengue fever and dengue hemorrhagic fever were reported from Saudi Arabia, Sudan and Yemen.